{"id":14730,"date":"2015-03-22T09:21:54","date_gmt":"2015-03-22T16:21:54","guid":{"rendered":"http:\/\/wkoopmans.ca\/notebook\/?p=14730"},"modified":"2015-03-22T11:51:49","modified_gmt":"2015-03-22T18:51:49","slug":"pentax-full-frame-and-aps-c-lenses","status":"publish","type":"post","link":"http:\/\/wkoopmans.ca\/notebook\/?p=14730","title":{"rendered":"Pentax Full Frame and APS-c Lenses"},"content":{"rendered":"

\"pentax_ff_prototype\"<\/a><\/span><\/span><\/span><\/span><\/span><\/p>\n

With Pentax announcing that they will be releasing their DSLR with the same size sensor as 35mm film (know now as ‘Full Frame’) I wanted to try a test with some lenses designed for a\u00a0APS-c digital image circle. Pentax refers to these as ‘DA’ lenses.\u00a0 There are some lenses that are designed for use with either format these lenses are designated as ‘DFA’, I’m not interested in these for this purpose, as I know they will work as would older lenses from film cameras.\u00a0 So back to the DA lenses.\u00a0\u00a0 It seems that the only lenses that can be considered to work with the larger format will be prime lenses (single focal length).\u00a0 The zoom lenses designed for APS-c cause heavy\u00a0vignetting and will likely need to be used in a crop mode rather than covering the entire full frame sensor.
\n\"PentaxMZ6_DALenses-3838\"<\/a><\/span><\/span><\/span><\/span><\/span><\/p>\n

Pentax SMC-DA* 50-135mm f\/2.8 ED [IF] SDM\u00a0,\u00a0 Pentax\u00a0SMC DA 50mm f\/1.8, \u00a0and the SMC DA 35mm f\/2.8 Limited macro<\/em><\/strong>
\nAn example of\u00a0the extreme vignetting\u00a0is this image taken with the DA*50-135 set at 50mm and f2.8
\n\"PentaxMZ6_LensTest_Mar2015_015\"<\/a><\/span><\/span><\/span><\/span><\/span><\/p>\n

You can see that it doesn’t come close to covering ‘Full Frame’ with severe vignetting.\u00a0 The situation is better at 135 stopped down to f4 but the vignetting is still heavy in the corners.
\n\"PentaxMZ6_LensTest_Mar2015_014\"<\/a><\/span><\/span><\/span><\/span><\/span><\/p>\n

So moving on to the prime lenses where there is a much better chance of them covering the full image circle of the 35mm frame.\u00a0 I should probably mention the fact that I used what I knew would be some bad film.\u00a0 It was some very out of date Kodak 400 but because my primary objective was to test the lenses for their coverage I choose to use it.<\/p>\n

First up is the DA 50 1.8 I took only 2 shots with it the first one at f4 and the second at f1.8 and it clearly covered the full 35mm frame with little to no vignetting in fact it seems perfectly suited to Full Frame.<\/p>\n\n\t\t